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Submission #80051

# Submission time Handle Problem Language Result Execution time Memory
80051 2018-10-18T13:25:03 Z Mahdi_Jfri Palindromes (APIO14_palindrome) C++14
8 / 100
 1000 ms 15572 KB 
#include<bits/stdc++.h>
using namespace std;

#define ll long long
#define pb push_back

const int maxn = 6e5 + 20;

string S;
int N, gap;
int sa[maxn], pos[maxn], tmp[maxn], lcp[maxn] , mn[maxn * 4];

vector<int> adj[maxn];

int sz[maxn] , w[maxn] , id = 1;

inline bool sufCmp(int i, int j)
{
	if (pos[i] != pos[j])
		return pos[i] < pos[j];
	i += gap;
	j += gap;
	return (i < N && j < N) ? pos[i] < pos[j] : i > j;
}

inline void buildSA()
{
	N = S.size();
	for(int i = 0; i < N; i++) sa[i] = i, pos[i] = S[i];
	for (gap = 1;; gap *= 2)
	{
		sort(sa, sa + N, sufCmp);
		for(int i = 0; i < N - 1; i++) tmp[i + 1] = tmp[i] + sufCmp(sa[i], sa[i + 1]);
		for(int i = 0; i < N; i++) pos[sa[i]] = tmp[i];
		if (tmp[N - 1] == N - 1) break;
	}
}

inline void buildLCP()
{
	for (int i = 0, k = 0; i < N; ++i) if (pos[i] != N - 1)
	{
		for (int j = sa[pos[i] + 1]; S[i + k] == S[j + k];)
			++k;
		lcp[pos[i]] = k;
		if (k)--k;
	}
}

void buildSeg(int s = 0 , int e = N - 1 , int v = 1)
{
	if(e - s < 2)
	{
		mn[v] = lcp[s];

		return;
	}

	int m = (s + e) / 2;

	buildSeg(s , m , 2 * v);
	buildSeg(m , e , 2 * v + 1);

	mn[v] = min(mn[2 * v] , mn[2 * v + 1]);
}

int GetLcp(int l , int r , int s = 0 , int e = N - 1 , int v = 1)
{
	if(l <= s && e <= r)
		return mn[v];
	if(r <= s || e <= l)
		return maxn;

	int m = (s + e) / 2;

	return min(GetLcp(l , r , s , m , 2 * v) , GetLcp(l , r , m , e , 2 * v + 1));
}

void buildTrie(int l = 0 , int r = N - 1 , int root = 0 , int K = 0)
{
	if(l == r)
	{
		if(N - sa[l] != K)
		{
			adj[root].pb(id);
			w[id] = N - sa[l] - K;
			sz[id++] = 1;
		}
		else
			sz[root]++;

		return;
	}

	int lcp = GetLcp(l , r) - K;

	if(lcp != 0)
	{
		adj[root].pb(id);
		w[id] = lcp;
		id++;
		buildTrie(l , r , id - 1 , K + lcp);

		return;
	}

	if(GetLcp(l , l + 1) - K == 0)
	{
		buildTrie(l , l , root , K);
		buildTrie(l + 1 , r , root , K);

		return;
	}

	int L = l + 1 , R = r;

	for(int i = r - 1; i >= l; i--)
		if(GetLcp(l , i) - K != 0)
		{
			buildTrie(l , i , root , K);
			buildTrie(i + 1 , r , root , K);

			return;
		}

	while(R - L > 1)
	{
		int M = (L + R) / 2;

		if(GetLcp(l , M) - K == 0)
			R = M;
		else
			L = M;
	}

	buildTrie(l , L , root , K);
	buildTrie(L + 1 , r , root , K);
}

ll res;

void dfs(int v , int d = 0)
{
	for(auto u : adj[v])
	{
		dfs(u , d + w[u]);
		sz[v] += sz[u];
	}

	res = max(res , 1LL * d * sz[v]);
}

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);

	cin >> S;
	N = S.size();
/*
	buildSA();
	buildLCP();
	buildSeg();
	buildTrie();
	
	dfs(0);*/

	for(int l = 0; l < N; l++)
		for(int r = l; r < N; r++)
		{
			string t = S.substr(l , r - l + 1);

			reverse(t.begin() , t.end());

			if(t != S.substr(l , r - l + 1))
				continue;

			int x = 0;
			for(int i = 0; i + r - l + 1 <= N; i++)
				if(t == S.substr(i , r - l + 1))
					x++;

			res = max(res , 1LL * x * (r - l + 1));
		}
	cout << res << endl;
}

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 14456 KB Output is correct
2 Correct 14 ms 14580 KB Output is correct
3 Correct 18 ms 14580 KB Output is correct
4 Correct 14 ms 14592 KB Output is correct
5 Correct 14 ms 14688 KB Output is correct
6 Correct 14 ms 14700 KB Output is correct
7 Correct 14 ms 14700 KB Output is correct
8 Correct 14 ms 14860 KB Output is correct
9 Correct 14 ms 14868 KB Output is correct
10 Correct 14 ms 14868 KB Output is correct
11 Correct 14 ms 14868 KB Output is correct
12 Correct 14 ms 14868 KB Output is correct
13 Correct 14 ms 14868 KB Output is correct
14 Correct 14 ms 14868 KB Output is correct
15 Correct 14 ms 14868 KB Output is correct
16 Correct 14 ms 14868 KB Output is correct
17 Correct 14 ms 14868 KB Output is correct
18 Correct 15 ms 14868 KB Output is correct
19 Correct 21 ms 14868 KB Output is correct
20 Correct 21 ms 14872 KB Output is correct
21 Correct 16 ms 14876 KB Output is correct
22 Correct 15 ms 14880 KB Output is correct
23 Correct 29 ms 14884 KB Output is correct
24 Correct 18 ms 14888 KB Output is correct
25 Correct 26 ms 14892 KB Output is correct
26 Correct 15 ms 14896 KB Output is correct
27 Correct 15 ms 14900 KB Output is correct
28 Correct 19 ms 14936 KB Output is correct
29 Correct 17 ms 14936 KB Output is correct
30 Correct 15 ms 14936 KB Output is correct
31 Correct 14 ms 14936 KB Output is correct
32 Correct 15 ms 14936 KB Output is correct

Subtask #2
0 / 15.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1071 ms 14936 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #3
0 / 24.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1080 ms 14936 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #4
0 / 26.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1064 ms 15052 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1085 ms 15572 KB Time limit exceeded
2 Halted 0 ms 0 KB -